Project Summary/Abstract Reducing hypoglycemia is an important aspect of management of type 1 diabetes in older adults, many of whom have hypoglycemic unawareness, cognitive impairment, or both. Clinical trials of existing automated insulin delivery systems have not included older adults in sufficient numbers to allow for focused evaluation of efficacy and quality of life impacts that may differ from those observed in younger age groups. The proposed research entitled ?A Randomized Cross-over Trial Evaluating Automated Insulin Delivery Technologies on Glycemic Outcomes and Quality of Life in Older Adults with Type 1 Diabetes? aims to evaluate the effectiveness of 1) hybrid closed loop (HCL) technology and 2) predictive low-glucose suspension (PLGS) on glycemic outcomes, QOL indicators and usability compared with sensor-augmented pump (SAP) therapy, as well as evaluate the safety of these technologies, in older adults with T1D. A secondary objective is to directly compare HCL with PLGS on these same outcomes. These aims will be achieved via a multi-center, randomized, crossover trial, consisting of three treatment arms over three 12-week periods, with the HCL treatment arm used during one period, the PLGS treatment arm used during one period and SAP treatment arm (control) used during one period. The crossover trial will be preceded by a run-in phase in which participants will receive training on using the study devices. The randomized trial will include 90 individuals, age at least 65 years old, with T1D for at least 1 year who have evidence of sensor measured hypoglycemia during the baseline run-in. The primary outcome is percent of time spent with glucose levels less than 70 mg/dl during each period. Other glycemic metrics, QOL assessments and system usability will be secondary outcomes. Occurrences of severe hypoglycemia, diabetic ketoacidosis, falls/fractures, emergency room visits, and hospitalizations also will be assessed. Following the cross-over trial, participants will be given the opportunity to use study devices for an additional 12 weeks to assess choice of system use (PLGS vs. HCL), long-term durability and safety in a more real-world setting with less frequent study contacts. Thus, it is imperative to assess whether more advanced technologies involving automation of insulin delivery can be successfully implemented into diabetes management of older adults.